INTERNAL COMBUSTION ENGINE PISTON AND METHOD FOR MANUFACTURING SAME

摘要

An outer circumferential part (36) is formed on the upper surface (the crown surface) of a crown part (14), along the outer circumference thereof. The outer circumferential part (36) is formed from a flat part (36a) orthogonal to the piston shaft, and notch parts (36b). The flat part (36a) constitutes the highest-positioned surface (the uppermost surface) of the crown surface. A tapered part (38) is formed on the inside of the outer circumferential part (36). The tapered part (38) is formed from a slanted part (38a) and notch parts (38b). The notch parts (38b) constitute the outer edge part of valve recesses (24, 26). An anodic oxide film (48) is formed over the entire area of the crown surface, except for the flat part (36a) and the notch parts (36b, 38b).